Pour 3 tbsp of oil into a small bowl. Finely grate in the lemon zest, add a pinch of sea salt and black pepper, and mix together. Place the cherry tomatoes in a 12–x 16-inch baking dish. Rub the flavored oil all over the ricotta and place in the center of the dish, then gently rub the remaining oil over the tomatoes. Add a splash of water to the dish, place in the oven, and roast for 45 minutes.

With 10 minutes to go, cook the spaghetti in a pan of boiling salted water according to the package instructions.
Lift the ricotta out of the baking dish, then shake the tomatoes off the vines, discarding the stalks. Add half a cup of pasta water to the dish and gently shake to loosen all the sticky goodness from the base. Drain the pasta and toss into the dish with a squeeze of juice, then break that ricotta over the top. Sprinkle over the arugula and olives toss together well, then serve with a drizzle of balsamic.